Patent US3882678A successfully refreshed from Google Patents.
US3882678A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic connecting valves for reserve pumps
Assignee: ZF Friedrichshafen AG
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Filing: 1974-06-05
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Granted: 1975-05-13
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Expires: 1994-06-05
Abstract
Abstract In systems using a main pump and a reserve pump where it is essential that pressure feed to a consumer unit, e.g., a vehicle booster steering device, be available in the event of failure of the main pump, the invention provides quick shifting to a reserve pump. The effect is achieved in two embodiments of the invention by means of a valve which is spring biased to a closed flow condition of the main stream from a main pump, but opening the main flow responsive to consumer unit demand, while, however, permitting continuous reserve pump flow to reach the consumer unit prior to such opening. A pilot stream from the main pump establishes a pressure differential on the valve to control response to main pump failure for cutting in the reserve pump. The pilot flow is through a pressure chamber means in which a drop in pressure due either to unit demand or main pump failure is effective to cause valve actuation for main flow opening, or valve opening for reserve pump flow. An important feature of the invention resides in the fact that the pressure drop is achieved either by loss of main pump pressure or reduction in discharge rate, e.g., due to a slipping drive belt of the main pump.
Inventors
- 👤 Rolf Fassbender
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:45
CPC Classifications
F; F15; F15B; F15B11/00; F15B11/16; F15B11/17; B; B62; B62D; B62D5/00; B62D5/06; B62D5/30; B62D5/32; F16; F16K; F16K11/00; F16K11/02; F16K11/06; F16K11/065; F16K11/07; F16K11/0716; Y; Y10; Y10T; Y10T137/00; Y10T137/2496; Y10T137/2559; Y10T137/2564; Y10T137/2572; Y10T137/2574; Y10T137/2579; Y10T137/2587
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
225 words
A valve for controlling main flow from a main pump and reserve flow from a reserve pump, to a consumer unit; comprising a housing having a main pump inlet and a reserve pump inlet; said valve having passage means for a pilot stream and main flow from said main pump; outlet means for main flow from said main pump and reserve flow from said reserve pump to a consumer unit; actuable valve means in said housing; said valve means and said housing having coacting elements relatively positionable to open main flow to said outlet means and close reserve flow or to close main flow and open reserve flow to said outlet means; bias means normally biasing said valve means to close main flow and open reserve flow to said outlet means; pressure differential means comprising upstream and downstream pressure chamber means operative to actuate said valve means to overcome said bias means to open main flow and close reserve flow upon increase of pressure differential; further comprising choke passage means operable to pass said pilot stream from said upstream to said downstream pressure chamber means; and a connection from said downstream pressure chamber means to said outlet means whereby a reduction in pressure differential to a predetermined value permits said bias means to actuate said valve means to effect reserve flow to said consumer unit.
Claim 2
Dependent Claim
225 words
A valve for controlling main flow from a main pump and reserve flow from a reserve pump, to a consumer unit; comprising a housing having a main pump inlet and a reserve pump inlet; said valve having passage means for a pilot stream and main flow from said main pump; outlet means for main flow from said main pump and reserve flow from said reserve pump to a consumer unit; actuable valve means in said housing; said valve means and said housing having coacting elements relatively positionable to open main flow to said outlet means and close reserve flow or to close main flow and open reserve flow to said outlet means; bias means normally biasing said valve means to close main flow and open reserve flow to said outlet means; pressure differential means comprising upstream and downstream pressure chamber means operative to actuate said valve means to overcome said bias means to open main flow and close reserve flow upon increase of pressure differential; further comprising choke passage means operable to pass said pilot stream from said upstream to said downstream pressure chamber means; and a connection from said downstream pressure chamber means to said outlet means whereby a reduction in pressure differential to a predetermined value permits said bias means to actuate said valve means to effect reserve flow to said consumer unit.
Claim 3
Dependent Claim
253 words
A valve for controlling main flow from a main pump and reserve flow from a reserve pump, to a consumer unit; comprising a housing having a main pump inlet and a reserve pump inlet; main flow outlet means for main flow from said main pump and for reserve flow from said reserve pump, to a consumer unit; actuable valve means in said housing; said valve means and said housing having coacting elements relatively positionable to open main flow to said outlet means and close reserve flow, or, to close main flow and open reserve flow to said outlet means; bias means normally biasing said valve means to close main flow and open reserve flow to said outlet means; pressure differential means comprising communicable upstream and downstream pressure chamber means effecting pressures operative on said valve means to actuate said valve means against said bias means to open main flow and close reserve flow upon relative increase of pressure in said upstream chamber means; said pressure differential means comprising pilot stream means providing pilot flow from said main pump to said upstream pressure chamber means to effect a normally higher pressure therein for maintaining said valve means in an actuated position; and a connection from said downstream pressure chamber means to said outlet means whereby relative increase of pressure therein reduces the differential pressure between said chambers a predetermined value in event of main pump failure to permit said bias means to actuate said valve means to effect reserve flow to said consumer unit.
Claim 4
Dependent Claim
253 words
A valve for controlling main flow from a main pump and reserve flow from a reserve pump, to a consumer unit; comprising a housing having a main pump inlet and a reserve pump inlet; main flow outlet means for main flow from said main pump and for reserve flow from said reserve pump, to a consumer unit; actuable valve means in said housing; said valve means and said housing having coacting elements relatively positionable to open main flow to said outlet means and close reserve flow, or, to close main flow and open reserve flow to said outlet means; bias means normally biasing said valve means to close main flow and open reserve flow to said outlet means; pressure differential means comprising communicable upstream and downstream pressure chamber means effecting pressures operative on said valve means to actuate said valve means against said bias means to open main flow and close reserve flow upon relative increase of pressure in said upstream chamber means; said pressure differential means comprising pilot stream means providing pilot flow from said main pump to said upstream pressure chamber means to effect a normally higher pressure therein for maintaining said valve means in an actuated position; and a connection from said downstream pressure chamber means to said outlet means whereby relative increase of pressure therein reduces the differential pressure between said chambers a predetermined value in event of main pump failure to permit said bias means to actuate said valve means to effect reserve flow to said consumer unit.
Claim 5
Dependent Claim
266 words
A valve for controlling main flow from a main pump and reserve flow from a reserve pump, to a consumer unit; comprising a housing having a main pump inlet and a reserve pump inlet; main flow outlet means for main flow from said main pump and for reserve flow from said reserve pump, to a consumer unit; actuable valve means in said housing; said valve means and said housing having coacting elements relatively positionable to open main flow to said outlet means and close reserve flow, or, to close main flow and open reserve flow to said outlet means; bias means normally biasing said valve means to close main flow and open reserve flow to said outlet means; pressure differential means comprising upstream and downstream pressure chamber means having pressures acting on said valve means operative to overcome said bias means and actuate said valve means to open main flow and close reserve flow; said differential pressure means comprisIng pilot stream means providing a pilot stream flowing from said upstream to said downstream pressure chamber means in an actuated position of said valve means when said main pump is operative to effect a relative reduction of pressure in said downstream pressure chamber means whereby a predetermined differential pressure maintains main flow to said outlet means; and a connection from said downstream pressure chamber means to said outlet means whereby a decrease in pressure in said upstream pressure chamber means to a predetermined value in event of main pump failure permits said bias means to actuate said valve means to effect reserve flow to said consumer unit.
Claim 6
Dependent Claim
266 words
A valve for controlling main flow from a main pump and reserve flow from a reserve pump, to a consumer unit; comprising a housing having a main pump inlet and a reserve pump inlet; main flow outlet means for main flow from said main pump and for reserve flow from said reserve pump, to a consumer unit; actuable valve means in said housing; said valve means and said housing having coacting elements relatively positionable to open main flow to said outlet means and close reserve flow, or, to close main flow and open reserve flow to said outlet means; bias means normally biasing said valve means to close main flow and open reserve flow to said outlet means; pressure differential means comprising upstream and downstream pressure chamber means having pressures acting on said valve means operative to overcome said bias means and actuate said valve means to open main flow and close reserve flow; said differential pressure means comprisIng pilot stream means providing a pilot stream flowing from said upstream to said downstream pressure chamber means in an actuated position of said valve means when said main pump is operative to effect a relative reduction of pressure in said downstream pressure chamber means whereby a predetermined differential pressure maintains main flow to said outlet means; and a connection from said downstream pressure chamber means to said outlet means whereby a decrease in pressure in said upstream pressure chamber means to a predetermined value in event of main pump failure permits said bias means to actuate said valve means to effect reserve flow to said consumer unit.
Claim 7
Dependent Claim
238 words
A valve for controlling main flow from a main pump and reserve flow from a reserve pump, to a consumer unit; comprising a housing having a main pump inlet and a reserve pump inlet; said valve having passage means for a pilot stream and main flow from said main pump; outlet means for main flow from said main pump and reserve flow from said reserve pump to a consumer unit; actuable valve means in said housing; said valve means and said housing having coacting elements relatively positionable to open main flow to said outlet means and close reserve flow, or, to close main flow and open reserve flow to said outlet means; bias means normally biasing said valve means to close main flow and open reserve flow to said outlet means; pressure differential means comprising upstream and downstream pressure chamber means operative to actuate said valve means to overcome said bias means to open main flow and close reserve flow upon increase of pressure differential; said pressure differential means being operable to permit flow of said pilot stream from said upstream to said downstream pressure chamber means and effecting a pressure drop in the course of said flow; and a connection from said downstream pressure chamber means to said outlet means whereby a reduction in pressure differential to a predetermined value permits said bias means to actuate said valve means to effect reserve flow to said consumer unit.
Claim 8
Dependent Claim
238 words
A valve for controlling main flow from a main pump and reserve flow from a reserve pump, to a consumer unit; comprising a housing having a main pump inlet and a reserve pump inlet; said valve having passage means for a pilot stream and main flow from said main pump; outlet means for main flow from said main pump and reserve flow from said reserve pump to a consumer unit; actuable valve means in said housing; said valve means and said housing having coacting elements relatively positionable to open main flow to said outlet means and close reserve flow, or, to close main flow and open reserve flow to said outlet means; bias means normally biasing said valve means to close main flow and open reserve flow to said outlet means; pressure differential means comprising upstream and downstream pressure chamber means operative to actuate said valve means to overcome said bias means to open main flow and close reserve flow upon increase of pressure differential; said pressure differential means being operable to permit flow of said pilot stream from said upstream to said downstream pressure chamber means and effecting a pressure drop in the course of said flow; and a connection from said downstream pressure chamber means to said outlet means whereby a reduction in pressure differential to a predetermined value permits said bias means to actuate said valve means to effect reserve flow to said consumer unit.
Claim 9
Dependent Claim
115 words
A valve as set forth in claim 4, said valve means comprising a slidable piston valve having a throughbore connecting with said upstream pressure chamber means; a choke passage in said piston valve connecting with said throughbore and with said downstream pressure chamber means in at least one position of said piston valve; a housing for said valve means in which said piston valve is slidable; said housing and piston valve having coacting grooves to effect or cut-off flow from said pumps to said consumer unit; a spring acting against said piston valve to bias it to a position wherein flow from said reserve pump is effected and flow from said main pump is cut-off.
Claim 10
Dependent Claim
41 words
A valve as set forth in claim 5, including a check valve in said outlet means to preclude flow from said pilot stream from short circuiting through said valve means from said outlet means when said piston valve is being actuated.
Claim 11
Dependent Claim
52 words
A valve as set forth in claim 5, including a check valve in said connection from said downstream chamber means to prevent flow from said reserve pump from short circuiting through said valve means and main pump when said piston valve is being actuated, in event of failure of said main pump.
Claim 12
Dependent Claim
72 words
A valve as set forth in claim 5, said housing having a bore; said piston valve being slidable in said bore; said pressure chamber means being portions of said bore at opposite respective ends of said piston valve; a wall across the throughbore of said piston valve; said choke passage being through said wall for effecting a continuous pilot stream to said consumer unit from said main pump through said check valve.
Claim 13
Dependent Claim
59 words
A valve as set forth in claim 5, said piston valve having a radial bore effecting said choke passage and connecting with said throughbore and being normally in pilot flow cut off position by bias of said spring and rEspective grooves in said piston valve and housing, whereby said pilot stream flows only upon actuation of said piston valve.
Claim 14
Dependent Claim
105 words
A valve as set forth in claim 5, including a check valve in said connection from said downstream chamber means to prevent flow from said reserve pump from short circuiting through said valve means when said piston valve is being actuated; said housing having a bore; said piston valve being slidable in said bore; said pressure chamber means being portions of said bore at opposite respective ends of said piston valve; a wall across the throughbore of said piston valve; said choke passage being through said wall for effecting a continuous pilot stream to said consumer unit from said main pump through said check valve.
Claim 15
Dependent Claim
35 words
A valve as set forth in claim 5, said housing having an exhaust outlet connectable with the reserve pump inlet when said valve means is in actuated position effecting main flow to said consumer unit.
Claim 16
Dependent Claim
155 words
A valve as set forth in claim 5, said piston valve having a radial bore effecting said choke passage and connecting with said throughbore and being normally in pilot flow cut-off position in coaction with said housing by bias of said spring and whereby said pilot stream flows only upon actuation of said piston valve; wherein said piston valve and housing have respective coacting grooves for control of flow from said pumps to said consumer unit; and wherein a groove of said piston valve and a groove of said housing are intermediate the connection from said downstream pressure chamber means and said radial bore and coact to prevent pilot stream flow when said piston valve is biased to said main flow cut-off, whereby to prevent flow from said reserve pump from short circuiting through said valve means and main pump when said piston valve is being actuated, in event of failure of said main pump.
References Cited (Backward Citations)
US2440371A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-12 | 1978-11-11 | 1979-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-12 | 1982-11-11 | 1983-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-12 | 1986-11-11 | 1987-05-13 | $7700.00 | Window Closed / Lapsed |